My 93 DX HB makes a weird noise at idle, sort of coming from the valvetrain(MAYBE), I can only hear it well when inside the car but it definitely comes from the engine. It is a dry tone kind of noise, low pitch and constant, tends to dissipate above 1200 rpms.
At first I thought that I needed to adjust the valves, I did but the noise remains the same.
I also changed the water pump, and adjusted ignition timing, changed the plugs, oil, coolant. Still the noise remains.
Any ideas?????
Sometimes I get a bad idle, the idle speed drops and stays that way, does not do it all the time.
Thanks

 

Alternator?

 

hmmmm, I would think that the alt would make a high pitvh noise if bad, but it is worth a look. The car runs great otherwise, it accelerates fine.
Thanks

 

Start taking your belts off, and see if its one of those, each time you take a belt off start it up..

Also does the noise go away or change when you push the clutch in? its very possible it could be a throw out bearing.

Jeff

 

Thanks, but I do not think it is the release bearing. The car makes the noise with the tranny at neutral and there is no change whatsoever if I push the clutch pedal and select first gear.
It seems to come from the engine itself. Have you ever heard the noise from a bad water pump bearing? Sounds a bit like a diesel, this is a similar noise but not as loud as a diesel noise, and is best noticed sitting inside the car at idle.

 

could be a belt with a bad spot on part of it..id get a belt dressing and wet down each belt one at a time and find out which one it is thru deduction..if the sound is still there *I have no idea*

 

I replaced both belts when I replaced the timing belt recently.
The noise was there before I replaced all belts and remains the same.
I do not think it is the belts, it is an engine kind of noise. hard to pinpoint.